/// tl_has_child(object)
/// @arg object
/// @desc Returns whether the timeline has the given object as a child.

var tl = argument0;

if (tl = app)
	return false

for (var i = 0; i < ds_list_size(tree_list); i++)
	with (tree_list[|i])
		if (id = tl || tl_has_child(tl))
			return true

return false
